CN104935643A - Digital trunk system data frame dynamic buffer processing method - Google Patents

Abstract

The invention discloses a digital trunk system data frame dynamic buffer processing method, solves the problem of contradiction between time delay of upper data transmission and processing and strict digital trunk air interface timing, and belongs to the field of wireless communication. According to the method, a channel machine performs statistics of the time delay of upper data transmission and processing in real time, and the time delay is regarded as the parameter to calculate and obtain an expected quantity of data frames in a dynamic buffer pool. When the actual quantity of the data frames in the dynamic buffer pool is equal to the expected quantity, the quantity of the data frames in the dynamic buffer pool is unchanged; when the actual quantity of the data frames in the dynamic buffer pool is smaller than the expected quantity, the quantity of the data frames in the dynamic buffer pool is increased; when the actual quantity of the data frames in the dynamic buffer pool is larger than the expected quantity, the quantity of the data frames in the dynamic buffer pool is reduced; in this way, in the condition that the time for air interface data sending is strictly controlled, the data transmitted from the upper layer can be accurately arranged in corresponding time slots to be transmitted.

Description

A kind of digital cluster system Frame dynamic buffering processing method

Technical field

The invention belongs to wireless communication field, particularly relate to a kind of digital cluster system Frame dynamic buffering processing method.

Background technology

Digital Clustering channel device system is the Digital Clustering wireless access system meeting Chinese Digital cluster national standard.This system is applicable to, in industry wireless private network, specifically comprise track traffic, electric power, harbour, airport, government, army etc.Digital Clustering channel device system achieves the wireless access functions such as protocol stack physical layer, MAC layer, radio-frequency receiving-transmitting, also provides local and remote administration function simultaneously.When the connection with switching center disconnects, the basic registration in native system coverage, the business such as calling and short message can be supported.System supports GPS, IEEE1588 isochronon method of synchronization, systematic function when ensure that seamless cell merge and service quality.System have employed pure IP networking technology and total system redundant technique, ensure that system application flexibility and system reliability.Compared to traditional channel device, have receiving sensitivity high, strong interference immunity, terminal mobility is good, the advantage that security of system is high.

For TETRA digital cluster system, in TETRA system, no matter each radio carrier, be up link or down link, be divided into 4 time slots all in time.Each time slot is called a physical channel, can be used for speech or data service, signaling or the two mixed transport.The timeslot number of up link and down link is equal, staggers in time the time difference (see Fig. 1) being equivalent to two time slots between the paired time slot of up-downgoing.In TETRA frame structure (see Fig. 2), each tdma frame has 4 time slots.18 tdma frames form a multi-frame.The 18th frame in multi-frame is used as control signal, is referred to as control frame.60 multi-frames form a superframe.Superframe is used for long repeating frame.

Due to Digital Clustering employing is TDMA technology, data need to be carried in fixing time slot and are sent out away, the time of each time slot is fixing, but the transmission of upper layer data and process have certain time delay, and this time is unfixed, which results in the data of giving on upper strata and may arrive in advance or delay, if delayed, the time slot that it needs carrying will be missed, can only wait until that the corresponding time slot of next frame sends again.In this case, just need a kind of mechanism, the real-time that the upper data that can ensure to eat dishes without rice or wine send.

Summary of the invention

Technical problem solved by the invention is: for the feature of digital cluster system frame structure, proposes and achieves a kind of data-interface based on dynamic pool mechanism.By measuring in real time and adding up the quantity of Frame in propagation delay time and dynamic conditioning Buffer Pool, solve the contradiction between transmission delay and the timing of strict numerical cluster air interface, ensure that the real-time process of air interface data.

The object of the present invention is achieved like this: a kind of digital cluster system Frame dynamic buffering processing method, comprises the following steps:

Step one: the actual quantity of Frame in the channel device dynamic pool of initialize digital group system;

Step 2: channel device adds up in current slot the mean value sending downlink data request for N time and receive the time difference that downlink data request is replied; Wherein, N is integer;

Step 3: channel device is according to the desired amt of Frame in the mean value calculation dynamic pool of time difference;

Step 4: channel device compares actual quantity and the desired amt of Frame in dynamic pool, if actual quantity is identical with desired amt, then makes the actual quantity of Frame in dynamic pool constant by transmission downlink data request; If actual quantity is greater than desired amt, then reduce the actual quantity of Frame in dynamic pool by not sending downlink data request; If actual quantity is less than desired amt, then increase the actual quantity of Frame in dynamic pool by sending downlink data request continuously;

Step 5: using subsequent time period as current slot, returns step 2;

Complete digital cluster system Frame dynamic buffering processing method.

Wherein, step 2 is specially:

S1: channel device sends downlink data request, and record the time sending downlink data request;

S2: the request of channel device downlink data receiving is replied, record receives the time of reply;

S3: channel device calculates it and sends downlink data request and the time difference of time receiving reply;

S4: repeat S1 to S3N time, obtain the mean value of N gained time difference; Wherein, N is integer.

Wherein, in S4, the mean value of time difference is:

$\stackrel{\‾}{\mathrm{\Δt}}=\frac{{\mathrm{\Σ}}_{n=1}^N\mathrm{\Δ}{t}_n}{N}$

In formula, for the mean value of time difference, Δ t is the time difference, and n is the number of times of seeking time difference.

Wherein, in step 3, the desired amt of Frame is:

$M=\left[\frac{\stackrel{\‾}{\mathrm{\Δt}}+T-1}{T}\right]$

In formula, M is the desired amt of Frame, for the mean value of time difference, T is a slot time, and [] expression rounds.

Wherein, if actual quantity is less than desired amt in step 4, then sends two downlink data requests continuously and make the actual quantity of Frame in dynamic pool increase by 1.

Compared with prior art the invention has the advantages that:

The method of the invention can ensure that when each time slot of eating dishes without rice or wine outwards sends data, data all in need are placed in time slot and are sent out away, can not cause accumulation or the disappearance of data.Improve the service efficiency of middle time slot of eating dishes without rice or wine to greatest extent, ensure that the accuracy that data send and real-time.

Accompanying drawing explanation

Fig. 1 is the corresponding relation of the TETRA uplink downlink time slot of prior art;

Fig. 2 is the frame structure of the TETRA of prior art;

Fig. 3 is the actual quantity adjustment flow process of Frame in dynamic pool of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the present invention will be further described in detail.

The invention discloses in a kind of digital clustering communication system, solve upper layer transport and processing delay and strict Digital Clustering and to eat dishes without rice or wine conflicting method between timing.This method increases treatment mechanism in channel device, the transmission on real-time statistics upper strata and processing delay, and the corresponding actual quantity adjusting Frame in dynamic pool.In dynamic pool, the actual quantity adjustment process (see Fig. 3) of Frame is specially: after channel device statistics upper layer transport and processing delay, with this time delay for calculation of parameter obtains the desired amt of Frame in dynamic pool.When the actual quantity of Frame equals desired amt in dynamic pool, keep the quantity of Frame in dynamic pool constant; When the actual quantity of Frame is less than desired amt in dynamic pool, increase the quantity of Frame in dynamic pool; When the actual quantity of Frame is greater than desired amt in dynamic pool, reduce the quantity of Frame in dynamic pool.Like this, when the time that data of eating dishes without rice or wine send is tightly controlled, ensure that upper strata is given the data come and can be placed on accurately in corresponding time slot and be sent out away.

Embodiment: the actual quantity arranging Frame in dynamic pool during channel device initialization is 4, often processes the data of 72 time slots, generates the desired amt of Frame in a dynamic pool, adjusts the actual quantity of Frame in Buffer Pool with this.A kind of digital cluster system Frame dynamic buffering processing method, comprises the following steps:

Step one: channel device sends an ascending time slot message, and to record current time point be Tn;

Step 2: the corresponding descending time slot message of channel device process, and to record current time point be Tn+1;

Step 3: the time difference Δ t calculating a time slot up-downlink message according to these two time points;

Step 4: the time difference of multi-frame totally 72 time slots in cumulative calculation current slot, the mean value of seeking time difference;

Wherein, the mean value of time difference is:

$\stackrel{\‾}{\mathrm{\Δt}}=\frac{{\mathrm{\Σ}}_{n=1}^N\mathrm{\Δ}{t}_n}{N}$

In formula, for the mean value of time difference, Δ t is the time difference, N=72.

Step 5: according to time slot 14167 microsecond, being converted to by the mean value of time difference is the unit of time slot, with this desired amt as Frame in dynamic pool;

Wherein, the desired amt of Frame is:

$M=\left[\frac{\stackrel{\‾}{\mathrm{\Δt}}+T-1}{T}\right]$

In formula, M is the desired amt of Frame, for the mean value of time difference, T is a slot time, and [] expression rounds, with T all in units of microsecond.

Such as, if the mean value of time difference be 28334 microseconds, then in dynamic pool, the desired amt M of Frame is 2; If the mean value of time difference be 46000 microseconds, then in dynamic pool, the desired amt M of Frame is 4.

Step 6: if current desired amt is 4, actual quantity is 4, then illustrate that actual quantity is synchronous with desired amt, sends the request of descending time slot data; If current desired amt is 8, actual quantity is 4, then illustrate that current time delay is comparatively large, need the data of asking descending time slot in advance, send the request of two descending time slot data continuously, the actual quantity of Frame in dynamic pool is added 1 simultaneously, become 5; If current desired amt is 3, actual quantity is 5, then illustrate that current time delay is less, data in simultaneous buffering pond have enough ensured to fill corresponding descending time slot, do not need the data of asking descending time slot, the actual quantity of Frame in dynamic pool is subtracted 1 simultaneously, become 4.

In such a manner, each multi-frame (1.02s) adjusts the desired amt of Frame in a dynamic pool, the actual quantity that can control Frame in dynamic pool is in real time close to desired value quantity, request msg can be shifted to an earlier date timely when delay is larger, descending time slot can not be caused idle, the data simultaneously no longer please looked for novelty when delay is less, the data in timely buffer release pond, can not in the accumulation becoming data.The contradiction perfectly solving network delay and eat dishes without rice or wine between timing.

Step 7: using subsequent time period as current slot, returns step one;

Complete digital cluster system Frame dynamic buffering processing method.

In sum, these are only preferred application example of the present invention, be not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. a digital cluster system Frame dynamic buffering processing method, is characterized in that comprising the following steps:

Step one: the actual quantity of Frame in the channel device dynamic pool of initialize digital group system;

Step 2: channel device adds up in current slot the mean value sending downlink data request for N time and receive the time difference that downlink data request is replied; Wherein, N is integer;

Step 3: channel device is according to the desired amt of Frame in the mean value calculation dynamic pool of time difference;

Step 4: channel device compares actual quantity and the desired amt of Frame in dynamic pool, if actual quantity is identical with desired amt, then makes the actual quantity of Frame in dynamic pool constant by transmission downlink data request; If actual quantity is greater than desired amt, then reduce the actual quantity of Frame in dynamic pool by not sending downlink data request; If actual quantity is less than desired amt, then increase the actual quantity of Frame in dynamic pool by sending downlink data request continuously;

Step 5: using subsequent time period as current slot, returns step 2;

Complete digital cluster system Frame dynamic buffering processing method.

2. a kind of digital cluster system Frame dynamic buffering processing method according to claim 1, it is characterized in that, described step 2 is specially:

S1: channel device sends downlink data request, and record the time sending downlink data request;

S2: the request of channel device downlink data receiving is replied, record receives the time of reply;

S3: channel device calculates it and sends downlink data request and the time difference of time receiving reply;

S4: repeat S1 to S3N time, obtain the mean value of N gained time difference; Wherein, N is integer.

3. a kind of digital cluster system Frame dynamic buffering processing method according to claim 2, it is characterized in that, in described S4, the mean value of time difference is:

$\stackrel{\‾}{\mathrm{\Δt}}=\frac{{\mathrm{\Σ}}_{n=1}^N\mathrm{\Δ}{t}_n}{N}$

In formula, for the mean value of time difference, Δ t is the time difference, and n is the number of times of seeking time difference.

4. a kind of digital cluster system Frame dynamic buffering processing method according to claim 1, it is characterized in that, in described step 3, the desired amt of Frame is:

$M=\left[\frac{\stackrel{\‾}{\mathrm{\Δt}}+T-1}{T}\right]$

In formula, M is the desired amt of Frame, for the mean value of time difference, T is a slot time, and [] expression rounds, with T all in units of microsecond.

5. a kind of digital cluster system Frame dynamic buffering processing method according to claim 1, it is characterized in that, if actual quantity is less than desired amt in described step 4, then sends two downlink data requests continuously and make the actual quantity of Frame in dynamic pool increase by 1.